ABUJA, Nigeria — Hundreds of Islamic extremists have surrendered in Nigeria and neighboring Cameroon following the military's recent victories with air and ground attacks, military authorities said Wednesday.

The Nigerian Defense Ministry has said it has killed hundreds of insurgents recently in the country's northeast.

Several militant commanders were among the dead including Mohammed Bashir, whom the Nigerian military identified as a double who posed in videos as Boko Haram leader Abubakar Shekau, a military statement said Wednesday.

Nigeria's military said it was victorious around Konduga town just 35 kilometers (22 miles) from Maiduguri, birthplace of Boko Haram and the headquarters of the military offensive to contain the Islamic uprising.

"It became apparent that the terrorists ... were determined to take over communities around Maiduguri, which is their prime target," the statement said, adding the insurgents made four attempts to take Konduga between Sept. 12 and 17.

It said 135 insurgents surrendered Tuesday night, some at Buni-Yadi some 200 kilometers (125 miles) west of Konduga and others at Michika, 165 kilometers (100 miles) south of Konduga.

Cameroon's defense ministry said more than 300 Boko Haram fighters have surrendered there in the past three weeks. Spokesman Lt. Col. Didier Badjeck told The Associated Press that the militants have given up their arms and asked for asylum in Cameroon. Their fate has not been decided.

Fighters from neighboring Cameroon, Niger and Chad have been identified fighting alongside Nigeria's homegrown Boko Haram group, which in recent weeks also has been attacking border towns and villages in Cameroon.

Boko Haram had seized a string of towns and declared an Islamic caliphate in a corner of northeast Nigeria before the setback suffered at Konduga.